Sciurus vulgaris

Recognition: Fur colour variable from bright ginger through to red and dark brown or black tinged with grey in winter; larger ear tufts in mid-winter which disappear by the summer; bushy tail which bleaches white by late summer in some individuals.

Head/body length: 180-240mm, tail about 175mm.

Weight: juveniles 100-150g; adults up to 350g.

Lifespan: They survive for up to six years in the wild.

Diet: Their main foods are tree seeds, especially hazel nuts and seeds from conifer cones. They also eat tree flowers and shoots, mushrooms and fungi from under tree bark. They often suffer periods of food shortage, especially during July.

GENERAL ECOLOGY

This is the only squirrel species native to Britain. It is active during the daytime, though in summer it may rest for an hour or two around mid-day. Squirrel nests, or dreys, are constructed of twigs in a tree fork, above a whorl of branches close to the stem of a conifer, or, less visibly, in a hole in a tree. They are lined with soft hair, moss and dried grass. Several squirrels may share the same drey, or use the same drey on different days.

Red squirrels spend about three-quarters of their active time above ground in trees and shrubs, and are at home in both conifer forests and broadleaved woodland. The distribution of red squirrels has declined drastically in the last 60 years and they are now extinct in southern England except for a few on the Isle of Wight and two small islands in Poole Harbour. Elsewhere in central Britain they are confined to rather isolated populations in Wales (notably Anglesey) and around Formby in Merseyside. Red squirrels are still widespread in the North of England and Scotland, and in Ireland, but even here their range is contracting.

Breeding can begin in mid-winter and continue through the summer, depending on the weather and how much food is available. Mating chases occur where several males follow a female who is ready to mate. During chases squirrels make spectacular leaps through the tree canopy and spiral up and down tree trunks. Females have one or two litters a year, usually of about 2-3 young. Juveniles are weaned at around 10 weeks, but do not breed until they are one year old. Red squirrels in favourable habitat can live at a population density of one squirrel per hectare of woodland. Often densities are lower than this.

CONSERVATION

Red squirrels are protected by law, and may not be intentionally trapped, killed or kept, or have their dreys disturbed except under licence from Natural England (NE), the Countryside Council for Wales (CCW) or Scottish Natural Heritage (SNH).

Red squirrels are considered vulnerable in Britain. However, very occasionally high densities in some Scottish forests can lead to economic damage to trees. In such cases, government agencies will assess whether to issue a licence to remove some of them.

Historically, red squirrel populations in Britain have fluctuated widely, the species disappearing from many areas at times and recolonising at a later date. However, in the 1920s red squirrels began to be replaced by grey squirrels, introduced to about 30 sites from eastern North America, between 1876 and 1929. Red squirrels seem unable to survive in the presence of greys, but the reasons for this are not fully understood. There is no evidence that grey squirrels aggressively chase out red squirrels, but recruitment of young red squirrels seems to be reduced in the presence of greys. Grey squirrels brought a disease, parapox virus, with them from America to which they are immune but which usually kills red squirrels. The key as to why grey have replaced red squirrels seems to be their ability to compete for food in different types of habitat. Red squirrels live in all types of woodland habitats from pure broadleaf, to mixed broadleaf and conifer, to pure conifer. However it is believed they prefer pure conifer forests because they can forage in them more efficiently and survive in them better than in broadleaf forest. Grey squirrels digest acorns better than red squirrels, so have done much better in southern Britain.

The only certain way to ensure the continued presence of red squirrels in an area is to keep grey squirrels out, or at least to keep their numbers low. This may be achieved by habitat management to alter the tree species composition and age structure of woodland to suit red but not grey squirrels. Favouring conifers, not oaks, would help, and in mixed woodland, small-seededdeciduous species like birch and rowan would at least inhibit greys. Special food hoppers which provide food for red squirrels but not the heavier grey squirrels, might help to tip the balance in favour of red squirrels. Re-introductions to large pine forests is a possible conservation tactic, but has so far met limited success. Further research into the health and welfare of red squirrels during captivity and all phases of a reintroduction programme is needed.

FREQUENT QUESTIONS

Can we re-introduce red squirrels to our wood?

No. Captive bred animals and a licence from NE/CCW/SNH would be needed first. Red squirrels are timorous and easily stressed. Reintroducing them to an unknown environment where they are in direct competition with greys is inhumane. Reintroductions will only work if the habitat is suitable, big enough and is being managed to encourage red and discourage grey squirrels.

Is there a distinct British race of red squirrel?

One has certainly been named: Sciurus vulgaris leucourus, this is the squirrel whose tail bleaches in summer (leucourus = white tail). Genetic evidence for a distinct British race is dubious (this might just be a colour form, but red squirrels have been repeatedly imported from Europe, effectively obscuring genetic distinctions).

FURTHER INFORMATION

Harris, S. & Yalden, D.W. (2008) Mammals of the British Isles,: Handbook, 4th edn.). The Mammal Society, Southampton.

Holm J. (1987) Squirrels. Whittet Books, London.

Holm J. (1989) The Red Squirrel.  Shire Natural History.